Method of operating a compact, low flow resistance aerosol generator

Abstract

A method is described comprising: providing a first heated volume flow of pressurized gas, a second volume flow of pre-heated dilution gas, and a third volume flow of fluid. A concentrated first aerosol is generated by exhausting at least a part of the first volume flow of pressurized gas and the third volume flow of fluid through a nozzle. A fourth volume flow of gas of opposite direction to the concentrated first aerosol is generated such that the concentrated first aerosol is arrested. Evaporation of the aerosol solvent is augmented with infrared radiation. The arrested first aerosol is then mixed with the second volume flow of dilution gas for generating a second aerosol that has been diluted. This aerosol is then concentrated with a virtual impactor.

What is claimed is: 
     
       1. A method for generating an aerosol, comprising:
 providing a first volume flow of pressurized gas; 
 pre-heating the first volume flow of pressurized gas; 
 providing a second volume flow of dilution gas; 
 pre-heating the second volume flow of dilution gas; 
 providing a third volume flow of fluid; 
 generating a concentrated first aerosol by exhausting at least a part of the first volume flow of pressurized gas and the third volume flow of fluid through a nozzle; 
 providing a fourth volume flow of gas of opposite direction to the concentrated first aerosol such that the concentrated first aerosol is arrested; and 
 mixing the arrested first aerosol with the second volume flow of dilution gas for generating a second aerosol that has been diluted. 
 
     
     
       2. The method according to  claim 1 , further comprising evaporating liquid from the second aerosol for generating a third aerosol comprising dry powder, gas and vapor. 
     
     
       3. The method according to  claim 2 , further comprising applying infrared irradiation for the evaporating of the liquid. 
     
     
       4. The method according to  claim 1 , wherein the pre-heating of the first volume flow of pressurized gas comprises guiding the first volume flow of pressurized gas through a gap between an inner cylindrical wall of a tube and an outer cylindrical wall of an tapered elongated infrared bulb. 
     
     
       5. The method according to  claim 4 , further comprising measuring the temperature of the pre-heated first volume flow of pressurized gas and controlling that temperature by a controller that controls a power supply to the elongated infrared bulb. 
     
     
       6. The method according to  claim 1 , wherein the step of pre-heating the second volume flow of dilution gas comprises guiding the second volume flow of dilution gas through a gap between an inner cylindrical wall of a tube and an outer cylindrical wall of a tapered elongated infrared bulb. 
     
     
       7. The method according to  claim 6 , further comprising measuring the temperature of the pre-heated second volume flow of dilution gas and controlling that temperature by a second controller that controls the power supply to the elongated infrared bulb. 
     
     
       8. The method according to  claim 1 , further comprising:
 dividing the first volume flow of pressurized gas into a first partial pressurized gas volume flow that is fed into the nozzle for generating the concentrated first aerosol and a second partial pressurized gas volume flow that is fed as the fourth volume flow into a counter-flow tube; and 
 exhausting the second partial pressurized gas volume flow through a counter-flow tube exit port into a direction that is substantially opposite to an exhaust direction of the concentrated first aerosol. 
 
     
     
       9. The method according to  claim 1 , further comprising:
 dividing the second volume flow of dilution gas into a first partial dilution gas volume flow that is fed through a central portion of a flow partitioner and a second partial dilution gas volume flow that is fed through a peripheral portion of the flow partitioner. 
 
     
     
       10. The method according to  claim 1 , further comprising generating the second volume flow of dilution gas by means of a blower. 
     
     
       11. The method according to  claim 10 , further comprising drying the second volume flow of dilution gas upstream of the blower in a drying chamber comprising a disposable desiccant. 
     
     
       12. The method according to  claim 9 , further comprising generating a partial second aerosol by mixing the first aerosol with the first partial dilution gas volume flow. 
     
     
       13. The method according to  claim 2 , further comprising compacting the third aerosol by generating a concentrated dry powder fourth aerosol comprising at least 80 percent of the dry particles of the third aerosol but only 10-20% of the volume flow of the third aerosol. 
     
     
       14. The method according to  claim 13 , further comprising decaying the deceleration eddys in the concentrated dry powder fourth aerosol in an eddy relaxation chamber. 
     
     
       15. The method according to  claim 14 , further comprising constricting the concentrated dry powder fourth aerosol in a cone shaped collector prior to outputting the concentrated dry powder fourth aerosol to a patient to be inhaled by the patient. 
     
     
       16. The method according to  claim 1 , further comprising pre-heating the fourth volume flow of gas.